The Ore-formation Geological Conditions And Prospecting Prediction Of Jinshan Gold Mineralization Zone In Boli County, Heilongjiang Province

Jinshan gold mineralization area is located in the Jiamusi massif where circumPacific tectonic domain superimpose and convert to Paleo-Asian Ocean tectonicdomain and. Tectonic movement and magmatic activity is intensity in the aera. Andthis mineralization area is also located in the middle of Mudanjiang-Jiamusi goldmetallogenic belt. It shows good ore potential for noble and multi-metals in the area.There are wide-spread variscan biltite granite and late-Yanshanian neutral-acidintrusive rock in the mineralization area, magmatic activity lay the foundation forgold deposit. Gold mineralization has close relationship with late-Yanshanian byke(especially for NW trend dioritic porphyrite dyke), mineralized bodies and dykes areparagenesis in space. Magmatic activity during late-Yanshanian are importantore-forming materials, hot and fluid resources, it’s important magnatic condition formineralization. Tectonic activity in the mineralization area is intense and it hasmulti-period characteristic, the major tread of fault structure are EW, NNW,NW andNE. Among, NW trend faults are important ore-reservoir structure. The wall rockalteration accompanying in the mineralize process includes silication, pyritization,chloritization and pyritization.Through the fluid inclusion analysis on the vein during main metallogenic epoch,we confirm that ore-forming fluid is NaCl-H2O system, fluid temperature higher than250~295℃，fluid salinity variation range between5％~9％NaCl eqv, density variesbetween0.8~0.95g/cm3, pressure variation mainly range between19~33MPa. Wepreliminary confirm that the mineralization type in Jinshan gold mineralization area ishydrothermalgenesis concerned with magmatic activity. Based on the analysis on soil geochemical survey, we establish the indicatorelements for prospecting and define the area of soil geochemical anomalies, then weprovide exploration geochemistry information for the continue exploration. Thoughgeophysical prospecting(electrical method) we further confirm the position and scaleof mineralization section in the deep, to provide information for establishingexploration geophysics indications and model.After analysising micronutrient levels of different geological units in themineralization area, we discuss the relationship between stratum, different phasemagmatic activity and mineralization. Combine with tectonic characteristics,Yanshannian dyke and the spatial distribution of ore body, we make sure theore-controlling rules of magmatic activity and tectonic structure. After comprehensiveconcluding the characteristics of geologic feature, spatial distribution of ore body,ore-controlling rules and physical-chemical environment, we summarize metallogenicmodel of the deposit.Based on the analysis of metallogenic geological conditions and enrichment ofmineralization, combine the characteristics geoghysical and geochemical prospectingannoly, we summarise collective geological prospecting indications for the deposit.(1) Geological indications: first, the NW trend fault structure that overly on theEW trend alteration belt control the distribution of Yanshanian neutral-acid dyke, it’simportant tectonic indications; second, Yanshannian dioritic porphyrite have a highcontent of gold, and it intergrowth with ore-body intimately, it’s important magmaticindication; third, silication, pyritization, chloritization and pyritization formaccompany mineralizing, they are important wall alteration indication.(2) Exploration geochemistry indication: Au annolies which have large area，high gold content, and combine with As, Ag, Sb, Bi composite component annolied,are advantageous district for gold mineralization, they are important soil geochemistryexploration indications.(3)Exploration geophysical indication： Influenced by silication and pyritization,IP intermediate gradient survey shows that gold mineralization bodies have highapparent resistivity and high polarizability. Locality, influenced by later fracture, mineralization bodies behive low resistivity and high polarizability. They areimportant exploration geophysical indications for looking for hidden gold orebody。On the basis of metallogenic geology analysis and metallogenic model,combinewith collective geological prospecting indications, and according to the rules fortarget prediction, we define3Ⅰ-level prospecting targets,2Ⅱ-level prospecting targets,l Ⅲ-level prospecting target.